He wanted to state how strongly he felt about his cause. He is not afraid of the war because he knows how much we really need it and how important it is to our country. He said, “I have no misgivings about, or lack of confidence in the cause in which I am engaged, and my courage does not halt or falter” (Sullivan Ballou)
He also wrote it to say how much he loves his wife because he knows that he has a good chance of dying in the war and wants to say goodbye to her so that she knows how much he loved her, but he said he loves his country more. “Sarah my love for you is deathless, it seems to bind me with mighty cables… and yet my love of Country comes over me like a
strong wind and bears me irresistibly” (Sullivan Ballou) He ended up dying a week after he wrote the letter in the Battle at Bull Run, and the letter never ended up getting delivered to Sarah.